#include <algorithm>
#include <iostream>
#include <vector>

std::vector<std::size_t> getReversalsToSort(const std::vector<int> &arr);
/**
 * Imagine a sort algorithm, that sorts array of integers by repeatedly
 * reversing the order of the first several elements of it.
 *
 * For example, to sort [12,13,11,14], you need to reverse the order of the
 * first two (2) elements. You will get [13,12,11,14]. Then you shall reverse
 * the order of the first three (3) elements, and you will get [11,12,13,14]
 *
 * For this assignment you shall implement function
 * that returns list of integers corresponding to the required reversals.
 * E.g. for given vector [12,13,11,14]
 * the function should return [2, 3].
 */
std::vector<std::size_t> getReversalsToSort(const std::vector<int> &arr) {

  // there's a slightly more fancy version of this but who cares
  // all we need is the elements sorted from least to greatest
  // sorting to get info might be cheating but eeeeeh it wasn't specified
  std::vector<int> sorted = arr;
  std::sort(sorted.begin(), sorted.end());

  std::vector<int> intermediate = arr;

  std::vector<std::size_t> ret = {};

  // a bit more explicit than necessary but my brain thought it was useful info
  std::vector<int>::const_iterator search_reference = arr.cbegin();
  std::size_t i = arr.size() - 1;
  for (auto elem = sorted.rbegin(); elem != sorted.rend(); elem++) {

    // using search reference so we don't find the same element over and over
    // again
    search_reference = std::find(search_reference, arr.cend(), *elem);

    std::size_t first_swap = search_reference - arr.cbegin();
    std::size_t second_swap = i;
    // remove false positives of elements already being in the correct spot
    if (first_swap != second_swap) {
      ret.push_back(first_swap);
      ret.push_back(second_swap);
    }
    i--;

    // checking if we're done early
    std::reverse(intermediate.begin(), intermediate.begin() + first_swap);
    std::reverse(intermediate.begin(), intermediate.begin() + second_swap);
    // TIL that std::equal exists
    if (std::equal(arr.cbegin(), arr.cend(), intermediate.cbegin(),
                   intermediate.cend())) {
      break;
    }
    // pushing the search reference past what we just found so we don't find
    // it again
    if ((elem + 1) != sorted.rend() && *(elem + 1) == *elem) {
      search_reference++;
    } else {
      search_reference = arr.cbegin();
    }
  }

  return ret;
}
int main(void) {
  std::cout << "{";
  std::vector<int> arr{12, 13, 11, 14};
  for (auto &e : getReversalsToSort(arr)) {
    std::cout << e << ",";
  }
  std::cout << "}\n";
}